Chap_13-language_and_the_Brain

Chap_13-language_and_the_Brain - COM D 2050 COM Chapt er...

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Unformatted text preview: COM D 2050 COM Chapt er 13: L anguage and t he Br ain L anguage and t he br ain Neur olinguist ics: field t hat st udies t he r elat ionship bet ween language and t he br ain ◦ Neur ologist s ◦ Psychologist s ◦ Speech-language pat hologist s 2 T her e is no sense of pain in t he br ain. 3 Br ain Br Why do we car e about t he neur al basis of l anguage? 4 St r oke St 3r d l eading killer in US Amer icans have a st r oke each 700,000 year What is a st r oke? 5 FYI -St r oke War ning Signs F YI Sudden numbness or weakness of face, ar m, or leg, especially on one side of t he body Sudden confusion, t r ouble speaking or u nder st anding Sudden t r ouble seeing in one or bot h eyes Sudden t r ouble walking, dizziness, loss of balance or coor dinat ion Sudden sever e headache wit h no k nown cause 6 Types of St r oke T ypes TI A I schemic H emor rhagic Aneur ysm 7 8 Cir cle of Willis Cir 9 Neur oanat omy N eur H uman ner vous syst em: ◦ Br ain ◦ Spinal cor d Br ain ◦ Cer ebr um, which is t he main mass of t he br ain 10 11 12 Brainstem, group of important structures at the base of the brain, that connect the brain to the spinal cord 13 Cer ebellum, at t ached t o t he back of t he br ainst em and is impor t ant for coor dinat ion of m ovement s 14 15 Br ain Br Br ain’s most basic funct ions ◦ Causing movement ◦ Pr ocessing sensat ion The br ain sends mot or commands t o t he muscles of t he body by way of t he br ainst em and spinal cor d, and t he spinal cor d t r ansmit s sensor y i nfo like t ouch and pain fr om var ious par t s of t he body. 16 Primary motor cortex (M1) Posterior parietal cortex Supplementary motor cortex (SMA) Premotor cortex (PMA) 17 H emispher es Cer ebr um ◦ Right hemispher e ◦ L eft hemispher e This is what is meant when people r efer t o r ight br ain ver sus left br ain. 18 19 20 Child br ain development Child M easur es of br ain act ivit y show t hat dur ing t he second half of a child’s f ir st year, t he pr efr ont al cor t ex (for et hought and logic) for ms synapses at such a r at e t hat it consumes t wice as much ener gy as an adult br ain. That pace cont inues f or t he child’s fir st decade of life. 21 Neur ons N eur Neur on: ◦ Cell body: r eceives signals fr om ot her n eur ons, pr ocess info ◦ Axon: sends signals t o ot her neur ons 22 CELL BODY Synapses Dendrites Nucleus Myelin sheath AXON Schwann cell Node of Ranvier Synaptic terminals 23 Early br ain gr owt h E arly Dur ing t he fir st mont h of life, t he n umber of connect ions or synapses, dr amat ically incr eases fr om 50 t r illion t o 1 quadr illion. I f an i nfant ’s body gr ew at a compar able r at e, his weight would incr ease fr om 8.5 lbs at bir t h t o 170 lbs at one m ont h. 24 Cer ebr al cor t ex Cer Out er layer of cer ebr al hemispher e M ade up of gr ay mat t er = cell bodies of neur ons Under cor t ex = whit e mat t er = axons 25 Parietal lobe Frontal lobe Occipital lobe Temporal lobe Cerebellum 26 L obes: Fr ont al st ar t s in t he fr ont , just behind t he f or ehead and goes almost half way back t o t he back of t he head. sends t he most of t he mot or commands t o t he muscles of your body t hat cause m ovement . lobe is impor t ant for per sonalit y, planning and decision m aking. 27 I t The fr ont al 28 29 L obes: Par iet al st ar t s behind t he fr ont al lobe. I t pr ocesses most of t he sensor y m emor y infor mat ion fr om t he body: ◦ Pain ◦ Temper at ur e ◦ Touch ◦ Sense of body posit ion 30 L obes: Occipit al in t he back of t he br ain I t is r esponsible mainly for vision. 31 L obes: Tempor al t he ext ension along t he side of t he br ain. I t underlies t he ear is impor t ant for hear ing and t he pr ocessing of bot h audit or y and v isual input . I t 32 5t h L obe of t he br ain 33 Pr imar y M ot or Cor t ex Pr Pr imar ily r esponsible for cont r olling t he muscles of your body. bot h t he L and R hemispher es ◦The PM C in t he L hemispher e (shown in book) cont r ols t he R side of your body. ◦The PM C in t he R hemispher e cont r ols t he L side of your body. I n 34 Primary motor cortex (M1) Posterior parietal cortex Supplementary motor cortex (SMA) Premotor cortex (PMA) 35 Br ain Br H omunculus: diagr am t hat shows you w hich par t s of t he pr imar y mot or cor t ex ar e devot ed t o cont r olling which par t s of t he body ht t p://facult y.washingt on.edu/chudler /f lash/h Cor t ical mapping: pr ocedur e of det er mining t he funct ions of ar eas of t he cer ebr al cor t ex by st imulat ing t hem dir ect ly 36 37 L ocalizat ion L ocalizat ion: at t r ibut ing ver y specific language funct ions t o specific br ain r egions. on t he assumpt ion t hat t he br ain is like ot her or gans in t he body over simplificat ions 38 Based Gr oss 39 40 41 Aphasia A phasia an impair ment of language f unct ion due t o localized br ain damage which leads t o difficult y in all language modalit ies t o var ying degr ees which include: -pr oduct ion of language -compr ehension -r eading -wr it ing 42 43 44 45 46 47 48 49 50 Br oca’s ar ea Br Ar ea labeled 1 in your book Br oca’s Aphasia ◦ slow, effor t ful, t elegr aphic (usually only nouns and ver bs, no gr ammat ical mor phemes) ◦ nonf luent speech (speaking at a slow r at e wit h m any pauses) ◦ u sually only mild pr oblems under st anding speech. ◦ I t is named aft er Paul Br oca, a Fr ench doct or. I n t he 1860s, he discover ed t hat damage t o t his ar ea i n t he left hemispher e (but not t he r ight ) caused ext r eme difficult y wit h speech pr oduct ion. 51 Br oca’s aphasia Br The following is an excer pt fr om T he Shatter ed M i nd (1974). David For d, was a 39 year old Coast Guar dsmen who suffer ed a st r oke and h ad Br oca’s aphasia. I n r esponse t o a quest ion about his work (r adio oper at or ), he said: “I ’m a sig…no… man…uh, well…again.” When asked what happened t o his speech, h e said: “H ead, fall, Jesus Chr ist , me no good, st r, st r …oh Jesus…st r oke.” 52 Wer nicke’s ar ea Wer The ar ea labeled 2 in t he book figur e at t he back of t he t op sur face of t he t empor al lobe is Wer nicke’s ar ea. Wer nicke’s Aphasia ◦ Fluent speech (speech pr oduced at a nor mal r at e and wit hout st r uggle) ◦ L ot s of t alking but it t ends t o be lacking of i mpor t ant nouns and ver bs and does not make m uch sense ◦ Speech likely t o cont ain neologisms (nonsense wor ds) ◦ Carl Wer nicke, a Ger man doct or in t he 1870s r epor t ed t hat pat ient s wit h damage in t his ar ea h ad difficult y compr ehending speech. 53 Wer nicke’s aphasia Wer The following is an excer pt fr om T he Shatter ed M i nd (1974). Philip Gor gan, a 72 year old but cher, had Wer nicke’s aphasia. I n r esponse t o a quest ion about why M r. Gor gan w as in t he hospit al, he said: “Boy, I ’m sweat ing, I ’m awfully ner vous, you know, once in a while I get caught up, I can’t ment ion t he t ar r ipoi, a m ont h ago, quit e a while, I ’ve done a lot well, I i mpose a lot , while, on t he ot her hand, you know w hat I mean, I have t o r un ar ound, look it over, t r ebbin and all t hat sor t of st uff.” 54 Ar cuat e fasciculus Ar The ar ea labeled 4 in t he book is t he ar cuat e fasciculus, not par t of t he cor t ex and not on t he sur face of t he hemispher e. Bundle of whit e mat t er fiber s (a bunch of axons) found below t he cor t ex in t he r egion bet ween Br oca’s and Wer nicke’s. I t pr ovides a connect ion bet ween t hose t wo ar eas. L esions in t his ar ea can pr oduce conduct ion aphasia. 55 Conduct ion aphasia Conduct Conduct ion aphasia ◦ Rar e ◦ I nt act audit or y compr ehension ◦ Under st and spoken wor ds ◦ Poor r epet it ion of ver bal mat er ials 56 Motor cortex Somatosensory cortex Pars opercularis Sensory associative cortex Visual associative cortex Broca’s area Visual cortex Primary Auditory cortex Wernicke’s area 57 T OT phenomenon TOT phenomenon: when you know t he wor d you want t o say, but you can’t r et r ieve it . St udies have shown t hat someone in a T OT st at e can usually: ◦ say what t he init ial sound of t he wor d is ◦ say how many syllables it has ◦ descr ibe t he st r ess pat t er n of t he wor d 58 TOT Phenomenon T OT M alapr opisms: pr oduct ion of similar sounding but incor r ect wor ds while in t he T OT st at e These char act er ist ics of t he t ip of t he t ongue st at e have been used t o infer how our ment al dict ionar y, our lexicon, is or ganized. When we ar e in t his t ip of t he t ongue st at e, w e t end t o pr oduce phonologically similar w or ds (similar sounding wor ds) in our st r uggle t o r et r ieve t he t ar get wor d. 59 Slips of t he t ongue Slips Spooner ism: a speech er r or r esult ing fr om an exchange of phonemes or wor ds wit hin a phr ase. ◦ Exchange of wor d-init ial sounds ◦ Exchange for wor d-final sounds ◦ Car r yover /per sever at ive/L t o R slip ◦ Ant icipat or y/R t o L slip 60 Types of slips of t he t ongue T ypes Exchange of wor d-init ial sounds (most common): Shu f lot s shot s Beel bet t er for for f lu feel bet t er Exchange for wor d-final sounds (r ar e): L oop befor e you leak for l ook befor e you l eap 61 Types of slips of t he t ongue T ypes Repet it ion of speech sounds (2 t ypes) ◦ Car r yover /per sever at ive/L t o R slip: B lack bloxes f or black boxes ◦ Ant icipat or y/R t o L slip: A t up of t ea f or a cup of t ea 62 Slips of t he t ongue Slips Used as evidence for some of t he syllable st r uct ur e const it uent s and phonot act ic r ules we have t alked about ◦ The fact t hat in “shu f lot s” t he fir st 2 consonant s of t he 2 wor ds ar e exchanged suggest s t hat at some level, an init ial consonant clust er is a dist inct unit of t he syllable. That unit is t he onset . ◦ The same is t r ue for t he nucleus and t he coda. T her e ar e slips of t he t ongue t hat involved exchanges or r epet it ions of nuclei and codas 63 Slips of t he ear Slips A pr ocessing er r or in which one w or d or phr ase is hear d as anot her 64 Dichot ic list ening t asks D ichot These t est s ar e based on t he fact t hat just like t he L hemispher e of t he br ain cont r ols t he R half of t he body, infor mat ion hear d by t he R ear goes pr imar ily t o t he L hemispher e. Bot h t he sensor y and mot or pat hways ar e cr ossed Right -ear advant age for language L eft -ear advant age for pr ocessing n on-linguist ic sounds 65 Dichot ic list ening t asks D ichot In t hese t asks, you use ear phones t o pr esent 2 differ ent signals (2 differ ent wor ds or maybe 1 r eal wor d and 1 nonsense wor d) t o t he 2 ear s at t he exact same t ime. You have t he subject r epeat what he hear s in one ear and ignor e what h e hear s in t he ot her ear. have shown t hat almost all of us ar e bet t er at r epeat ing what is said t o t he R ear t han w hat is said t o t he L ear. St udies 66 Dichot ic list ening t asks D ichot We have r ight -ear Because what advant age for language. comes int o t he R ear goes mainly t o t he L hemispher e, we conclude t hat t he L h emispher e must be dominant for language for a per son who has a R ear advant age for language. of us have a left -ear advant age for pr ocessing non-linguist ic sounds (music, envir onment al noises, bir d calls, et c..) M ost 67 Cr it ical per iod Cr Ther e seems t o be a cr it ical per iod f or language lear ning fr om bir t h up u nt il puber t y. a child does not acquir e language dur ing t his per iod, he or she will h ave gr eat difficult y lear ning it lat er on. I f 68 Genie Genie Genie’s st or y came out in 1970. Fir st 13 year s of her life t ied t o a chair in a dark r oom and was beat en if she made any noises, so she did not acquir e any l anguage. Dichot ic list ening t est : st r ong left -ear advant age for language Rehab pr ogr ams for t r aining R h emispher es of people wit h aphasia due t o L hemispher e st r oke t o t ake over l anguage funct ions, but t hey have mixed r esult s 69 ...
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This note was uploaded on 02/21/2010 for the course COMD 2050 taught by Professor Collins during the Spring '08 term at LSU.

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